Violent behavior in schizophrenia is a major public health problem. It is a frequent reason for psychiatric admission and an obstacle to successful reintegration of patients in the community. There is strong evidence that neurocognitive impairments play an important role in this violence. The current application proposes to develop a framework to understand the neurophysiological and neuroanatomical deficits present in violent schizophrenics and compare these to deficits present in non- violent schizophrenics and non-psychotic psychopaths. We will evaluate basic cognitive processes that are involved in the control of violent behavior, including inhibitory control and behavioral monitoring, through the use of functional magnetic resonance imaging (fMRI) and event-related potentials (ERP) in four different groups (1) violent schizophrenics (VS), (2) non-violent schizophrenics (NVS) (3) violent psychopaths (P) and (4) healthy controls (HC). We expect that: 1. Both P and VS will exhibit an abnormal pattern of activations in a specific neural circuit that is responsible for critical response inhibitory functions, as evidenced by behavioral, ERP and fMRI indices. 2. In the presence of emotionally arousing stimuli, the P and VS will exhibit divergent abnormalities. In the VS such stimuli produce excessive limbic and decreased fronto-temporal activation, while in the P group, such stimuli elicit less limbic and greater fronto-temporal activation. 3. We expect that the VS but not the P will evidence behavioral monitoring problems. NVS's problems will be greater than P and HC. A total of 160 subjects will receive all evaluations: 40 VS, 40 P, 40 NVS and 40 HC. In addition to fMRI's and ERP's, patients will receive a comprehensive evaluation, which will include neuropsychological, neurological and psychiatric evaluations.